Image-forming device having cooling mechanism for cooling a reading unit without overcooling a fixing unit

Abstract

An image-forming device includes a casing, a driving roller, a conveying belt, a photosensitive unit, a fixing unit, a reading unit, a fan, and a first partition wall. The casing has a wall formed with an air inlet port and defines an inner space. The air inlet port has a top end portion and a bottom end portion. The photosensitive unit is configured to form a predetermined pattern on the conveying belt. The fixing unit has a top edge portion and a bottom edge portion. The reading unit is provided adjacent to the driving roller and is configured to read a predetermined pattern formed on the conveying belt. The fan is provided on an upper section of the inner space. The fan transfers air from inside the casing to outside the casing. The first partition wall is located in the upper section of the inner space. The fan is provided on one side of the first partition wall and the fixing unit is provided on another side thereof. The first partition wall has a bottom end. The bottom end of the first partition wall is positioned below the top edge portion of the fixing unit and above the upper part of the conveying belt. The air inlet port is vertically in a lower position than the fan.

1. An image-forming device comprising:
 a casing that has a wall formed with an air inlet port and defines an inner space, the air inlet port having a top end portion and a bottom end portion; 
 a driving roller that is provided in the casing and defines an axial direction; 
 a conveying belt that is movably supported on the driving roller and is configured to convey a recording sheet in a sheet conveying direction perpendicular to the axial direction; 
 a photosensitive unit that is provided above the conveying belt and has at least one photosensitive drum configured to form a developer image to be transferred onto the recording sheet on the conveying belt, the photosensitive unit being configured to form a predetermined pattern on the conveying belt; 
 a fixing unit that is disposed to receive the recording sheet conveyed by the conveying belt and is configured to fix the developer image on the recording sheet by heat, the fixing unit having a top edge portion and a bottom edge portion; 
 a reading unit that is provided adjacent to the driving roller and is configured to read the predetermined pattern formed on the conveying belt; 
 a fan that is provided in an upper section of the inner space separated from a lower section of the inner space by an upper part of the conveying belt moving toward the fixing unit, the fan configured to transfer air from inside the casing to outside thereof; and 
 a first partition wall that is located in the upper section of the inner space, the fan being provided on one side of the first partition wall and the fixing unit being provided on another side thereof, the first partition wall having a bottom end, 
 wherein the bottom end of the first partition wall is positioned below the top edge portion of the fixing unit and above the upper part of the conveying belt, and the air inlet port is vertically in a lower position than the fan, and 
 wherein the air inlet portion is configured to direct air below the bottom edge portion of the fixing unit toward the reading unit. 
 
   
   
     2. The image-forming device according to  claim 1 , wherein the photosensitive unit has a plurality of photosensitive drums arranged along the sheet conveying direction, each of the plurality of photosensitive drums being configured to form a developer image to be transferred onto the recording sheet on the conveying belt. 
   
   
     3. The image-forming device according to  claim 1 , wherein the top end portion of the air inlet port is positioned below the bottom edge portion of the fixing unit. 
   
   
     4. The image-forming device according to  claim 1 , wherein the reading unit includes a plurality of reading sensors arranged along the axial direction, the plurality of reading sensors having a first sensor disposed in confrontation with one end portion of the driving roller and a second sensor disposed in confrontation with another end portion of the driving roller, a distance between the first sensor and the second sensor in the axial direction being shorter than a length of the air inlet port in a direction parallel to the axial direction. 
   
   
     5. The image-forming device according to  claim 4 , wherein a width of the partition wall in the direction parallel to the axial direction is longer than the length of the air inlet port. 
   
   
     6. The image-forming device according to  claim 5 , wherein the fan is provided above the one end portion of the driving roller, the first partition wall having one end portion and another end portion in the axial direction wherein the fan is provided at the one end portion of the first partition wall, and the another end portion of the first partition wall is formed with a connecting hole for allowing the one side and the another side of the first partition wall to be in fluid communication with each other. 
   
   
     7. The image-forming device according to  claim 1 , wherein the reading unit includes an optical sensor, and the air inlet port includes a plurality of strip louvers forming a louver window. 
   
   
     8. The image-forming device according to  claim 7 , wherein each of the plurality of strip louvers has an inner edge and an outer edge and is inclined with respect to a horizontal direction, the outer edge being positioned below the inner edge. 
   
   
     9. The image-forming device according to  claim 1 , farther comprising a second partition wall provided between the first partition wall and the photosensitive unit and covering the fan, the first partition wall and the second partition wall forming a duct. 
   
   
     10. An image-forming device comprising:
 a casing that has a wall formed with an air inlet port and defines an inner space; 
 a driving roller; 
 a conveying belt that is movably supported on the driving roller and is configured to convey a recording sheet in a sheet conveying direction perpendicular to the axial direction; 
 a photosensitive unit that is provided above the conveying belt and has at least one photosensitive drum configured to form a developer image to be transferred onto the recording sheet on the conveying belt, the photosensitive unit being configured to form a predetermined pattern on the conveying belt; 
 a fixing unit that is disposed to receive the recording sheet conveyed by the conveying belt and is configured to fix the developer image on the recording sheet by heat; 
 a reading unit that is provided adjacent to the driving roller and is configured to read the predetermined pattern formed on the conveying belt; 
 a fan; and 
 an air flow channel formed between the air inlet port and the fan, a majority of air introduced into the inner space through the air inlet port being transferred outside the casing by the fan, 
 wherein the reading unit is disposed in the air flow channel, the fixing unit is disposed in a position offset from the air flow channel, and the air inlet portion is configured to direct air below the bottom edge portion of the fixing unit toward the air flow channel. 
 
   
   
     11. The image-forming device according to  claim 10 , wherein the air flow channel comprises a partition wall that is configured to guide the majority of air toward the fan. 
   
   
     12. The image-forming device according to  claim 10 , wherein the air flow channel comprises a partition wall that partitions the fixing unit at least partially from the air flow channel. 
   
   
     13. The image-forming device according to  claim 10 , wherein the air flow channel comprises a duct. 
   
   
     14. The image-forming device according to  claim 1 , wherein the reading unit includes a plurality of reading sensors arranged along the axial direction, the plurality of reading sensors including a first sensor disposed in confrontation with one end portion of the driving roller and a second sensor disposed in confrontation with another end portion of the driving roller, a length of the air inlet port in a direction parallel to the axial direction being longer than a distance between the first sensor and the second sensor in the axial direction. 
   
   
     15. The image-forming device according to  claim 9 , wherein the duct has an opening that opens toward the reading unit. 
   
   
     16. An image-forming device comprising:
 a casing that has a wall formed with an air inlet port and defines an inner space, the air inlet port having a top end portion and a bottom end portion; 
 a driving roller that is provided in the casing and defines an axial direction; 
 a conveying belt that is movably supported on the driving roller and is configured to convey a recording sheet in a sheet conveying direction perpendicular to the axial direction; 
 a photosensitive unit that is provided above the conveying belt and has at least one photosensitive drum configured to form a developer image to be transferred onto the recording sheet on the conveying belt, the photosensitive unit being configured to form a predetermined pattern on the conveying belt; 
 a fixing unit that is disposed to receive the recording sheet conveyed by the conveying belt and is configured to fix the developer image on the recording sheet by heat, the fixing unit having a top edge portion and a bottom edge portion; 
 a reading unit that is provided adjacent to the driving roller and is configured to read the predetermined pattern formed on the conveying belt; 
 a fan that is provided in an upper section of the inner space separated from a lower section of the inner space by an upper part of the conveying belt moving toward the fixing unit, the fan configured to transfer air from inside the casing to outside thereof; and 
 a first partition wall that is located in the upper section of the inner space, the fan being provided on one side of the first partition wall and the fixing unit being provided on another side thereof, the first partition wall having a bottom end, 
 wherein the bottom end of the first partition wall is positioned below the top edge portion of the fixing unit and above the upper part of the conveying belt, and the air inlet port is vertically in a lower position than the fan, and 
 wherein the reading unit includes a plurality of reading sensors arranged along the axial direction, the plurality of reading sensors having a first sensor disposed in confrontation with one end portion of the driving roller and a second sensor disposed in confrontation with another end portion of the driving roller, a distance between the first sensor and the second sensor in the axial direction being shorter than a length of the air inlet port in a direction parallel to the axial direction. 
 
   
   
     17. The image-forming device according to  claim 16 , wherein a width of the partition wall in the direction parallel to the axial direction is longer than the length of the air inlet port. 
   
   
     18. The image-forming device according to  claim 16 , wherein the fan is provided above the one end portion of the driving roller, the first partition wall having one end portion and another end portion in the axial direction wherein the fan is provided in the one end portion of the first partition wall, and the another end portion of the first partition wall is formed with a connecting hole for allowing the one side and the another side of the first partition wall to be in fluid communication with each other. 
   
   
     19. The image-forming device according to  claim 16 , wherein the reading unit includes an optical sensor and the air inlet port includes a plurality of strip louvers forming a louver window. 
   
   
     20. The image-forming device according to  claim 19 , wherein each of the plurality of strip louvers has an inner edge and an outer edge and is inclined with respect to a horizontal direction, the outer edge being positioned below the inner edge. 
   
   
     21. The image-forming device according to  claim 16 , further comprising a second partition wall provided between the first partition wall and the photosensitive unit and covering the fan, the first partition wall and the second partition wall forming a duct, the duct having an opening that opens toward the reading unit.